Latch-spring fastener.



B. R. QRAMPTON. LATCH SPRING FASTENER.'Y

PPLICATION FILED JULY 3l. 1915.-* V' to the base plat' e.V The base plate com- UNIT sTATEs PRESSURE FASTENER COMPANY, OF DETROIT, MICHIGAN, A. CORPORATION .0F

. MICHIGAN.

LATCH-SPRING vFASTENIEZB..

Specification of Letters Patent.

ratenteuoct. Ia, i915.

Application filed July 31, 1915. S'eria1No.42,903.

T 0 all wlw/m it may concern;

Be it known that I, Basily It.Y CRAMPTON, a citizen of the United States, residing at Detroit, county of IVayne, State of Michigan. have invented a certain new and useful Improvement in Latch-Spring Fasteners,V and declare the following to be a. full, clear, and exact description of the same, such as will enable others skilledin the art to which it pertains to make and use the same, reference being had to the accompanying drawings, which form a part of this specification.

'This invention relates to improvements in latches especially7 to' improvements in that type of latch which operates upon the toggle-arm 'principle- The improvements embodied in the presentapplication relate to` a new way of mounting the spring upon the base plate whereby the spring has considerable freedom of action, thereby -very materially increasing its life.

In the drawings, Figure l, is a longitudinal section through the spring and base plate showing the toggle arms in elevation. Fig. 2, is a longitudinal section of the blank from which the base plate is stamped, showing how the center of the blank is raised up to form a support for the spring.' Fig. 3, is a plan view ofthe base plate.

The arrangement of the toggle parts is shown in Fig. l. These comprise a pair of toggle arms held together in the center by a button a and yieldingly prevented from approaching toward their dead center by reason of the pressure of the spring ends o. The shoulders o act as stops to prevent the toggle arms opening out farther than shown in Fig. l. The ends of the springs b are curled over to form L bearing upon which the toggle arms ,turng the toggle arms being notched to receive the, bearing. This much of the invention is'old.

The invention here/soughtto be secured is the means by which the spring l is secured prises a blank, as shown in Fig. 2. This blank is slotted at f, f; the metal between the slots is-then pressed up, as shown by the dotted lines in Fig. 2, to form a boss g. Portions of the side of t'he boss are turned over 'to form retaining lusgs h. The spring is passed through the slots y", f and the re- 'taining lugs I, are then pressed down over the spring. This not only tends to retain .the spring against longitudinal movement and lateral movement, but it also serves to slightly bow the spring in, so as to keep it out of contact with the member to which the base plate is secured.

If desired, the spring may vbe provided with a centrally located opening z' and into this maybe pressed a--point j in the boss. This alsovserves to locate and position the spring with respect to thev base plate.l It,

in connection with the lugs f, prevents the longitudinal shifting 'of the spring.

It has been found by actual tests that the life of a spring secured to a base plate in the manner described above is very materially lengthened. This is dueto the fact that-there is considerable freedom of action between the spring and the base plate, not only at the point'whe're the spring first comes into contact with the base plate but all along those portions where the spring 'and the boss of the base plate are substantially parallel. p v

By securing the spring on the under side of the plate at the springs center and holding it away from adjacent surfaces at the back of the spring, as by the boss for instance, the two portions of the spring on the sides of the fastening are free to vibrate from the center ofthe spring instead of at the Zones where the spring legs have a parallel abutting relation with the base plate as would be the case where the spring is clamped orl riveted to the top of the base plate and ',lies'directly thereagainst. Hence when the toggle levers pass dead center .and spread the vlegsof the U, some of the binding`strains are taken `at the center of the spring as well as at the zones where the legs are bent upwardly.

IVhat I claim is:

1. In a latch, the combination of a pair of -toggle arms, a U-like spring upon the free end of which the toggle arms are pivoted,

yand abase plate providedwith a portion arranged to form a free space or chamber thereunder, the said U-like spring being Iastened at its middle to the under side of said www' said U-like spring in a given position withl respect to the base plate.

l. In a latch, the combination of a pan' of toggle arnis. a U-like flat spring upon4 the ends of which the toggle arlns are pivoted, a base plate provided with a pan' of slots,`

anda boss raised between the slots. said U- like. spring passing through the slots and under the bossi, the said metal forming the base being struck out in lugs which are bent over to engage the sides ot' the spring under the boss.

In a latch, thecoinbination ot' a pair oic toggle arlns, a flat U-like spring upon the free ends of which the toggle arms are pivoted, a base plate provided with a pair of slots, and a boss raised between the slots, the said U-like spring vpassing through slots and under the boss, lneans t'or connecting the sides of the spring with the said boss, said spring being provided with a 'Central openingv and the said 'boss being provided with a struck-in portion' which engages in v*said o )ening to )osition the said s )rino with respect tothe base.

1n testnnon)v whereoi, I sign th1s specitication.

BASTIA R. CRAMPTON. 

